How iOS decides which wireless network to auto-join

When auto-joining networks, iOS starts with the most preferred network, followed by private networks, then public ones.

When your iOS device evaluates service set identifiers (SSIDs) and determines which network to auto-join, it will try to connect to networks in this order:

Your "most preferred" network

The private network you most recently joined

A private network

A public network

Public networks are designed for general access in public places like a hotel, airport or coffee shop. Some other examples include Hotspot 2.0, Passpoint, EAP-SIM, or Wi-Fi connections that are provided by some cellular carriers and cable providers. Private networks are any other network, including those set up in homes and offices and the Personal Hotspot on your iOS device.

Known networks are "scored" based on your actions. If you manually switch to an SSID, its score increases. If you manually disconnect from an SSID, its score decreases. "Most preferred" networks have higher scores.

If iOS finds multiple networks after evaluating the above criteria, iOS prioritizes SSIDs by security level and chooses one based on the following order: